Heat produced by electronic equipment can have adverse effects on the performance, reliability and useful life of the equipment, so heat control can be critical to reliable operation. One environment where heat control may be critical is a data center containing racks of electronic equipment, such as servers and CPUs. A data center may contain hundreds of, such racks. To address the heat generated by electronic equipment, such as the rack-mounted electronic equipment of a modern data center, air cooling devices have been used to provide a flow of cool air to the electronic equipment. In the data center environment, such cooling devices may be referred to as computer room air conditioner (“CRAC”) units. These CRAC units intake warm air from the data center and output cooler air into the data center. The electronic equipment in a typical rack is cooled as the cool air is drawn into the rack and over the equipment. The air is heated by this process and exhausted out of the rack.
Air conditioning units in a data center or computer room are a major source of energy consumption. Attempts to increase the efficiency of a CRAC unit have focused on using external water or air for cooling. Water-based cooling generally involves water flow either overhead or under the floor. Air-based cooling brings outside air into the data center.